The Agent Skills Directory

[COMMAND_EXECUTION]: The skill interacts with the user's environment by calling the 21st CLI for UI generation and iteration tasks.
Evidence: The skill utilizes commands such as 21st generate, 21st iterate, and 21st take to manage UI drafts.
[INDIRECT_PROMPT_INJECTION]: The skill processes UI code and specifications generated by an external AI service, presenting a standard ingestion surface for third-party content.
Ingestion points: Data enters the agent's context through the output of the 21st take command (HTML or copy-prompts).
Boundary markers: The instructions explicitly advise treating the output as a "design spec" and rebuilding it rather than pasting raw code verbatim.
Capability inventory: The skill is intended to help the agent "pull the final code into the project," which involves file-writing capabilities.
Sanitization: The skill implements mitigation by guiding the agent to interpret the results as design instructions rather than executable code.
[EXTERNAL_DOWNLOADS]: The skill is built around the use of the @21st-dev/cli package, which is the official tool from the skill author.

21st-ai